Nanohybrid polymers for ophthalmic applications

ABSTRACT

The present invention relates to novel materials particularly useful for ophthalmic applications and methods for making and using the same. More particularly, the present invention relates to relatively soft, optically transparent, foldable, high refractive index Materials particularly suited for use in the production of intraocular lenses, contact lenses, and other ocular implants and to methods for manufacturing and using the same.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not Applicable

FIELD OF THE INVENTION

The present invention relates to novel materials particularly useful forophthalmic applications and methods for making and using the same. Moreparticularly, the present invention relates to relatively soft,optically transparent, foldable, high refractive index materialsparticularly suited for use in the production of intraocular lenses,contact lenses, and other ocular implants and to methods formanufacturing and using the same.

BACKGROUND OF THE INVENTION

Since the 1940's optical devices in the form of intraocular lenses(IOLs) have been utilized as replacements for diseased or damagednatural ocular lenses. In most cases, an intraocular lens is implantedwithin an eye at the time of surgically removing the diseased or damagednatural lens, such as for example, in the case of cataracts. Fordecades, the preferred material for fabricating such intraocular lenseswas poly(methyl methacrylate), which is a rigid, glassy polymer.

Softer, more flexible IOLs have gained in popularity in recent years dueto their ability to be compressed, folded, rolled or otherwise deformed.Such softer IOLs may be deformed prior to insertion thereof through anincision in the cornea of an eye. Following insertion of the IOL in aneye, the IOL returns to its original, pre-folded shape due to the memorycharacteristics of the soft material. Softer, more flexible IOLs as justdescribed may be implanted into an eye through an incision that is lessthan 4.0 min i.e., much smaller than the 5.5 to 8.0 mm necessary toimplant more rigid IOLs. A larger incision is necessary for more rigidIOLs because the lens must be inserted through an incision in the corneaslightly larger than the diameter of the inflexible IOL optic portion.Accordingly, more rigid IOLs have become less popular in the marketsince larger incisions have occasionally been found to be associatedwith an increased incidence of postoperative complications, such asinduced astigmatism.

With recent advances in small-incision cataract surgery, increasedemphasis has been placed on developing soft, foldable polymer materialssuitable for use in artificial IOLs. In general, these materials fallinto one of three categories: hydrogels, silicones and low glasstransition temperature acrylics.

In general, high water content hydrogel materials have relatively lowrefractive indexes, making them less desirable than other materials withrespect to minimal incision size. Low refractive index materials requirea thicker IOL optic portion to achieve a given refractive power.Silicone materials may have a higher refractive index than high-watercontent hydrogels, but tend to unfold too rapidly after being placed inthe eye in a folded position. A too rapid unfolding of a folded lens canpotentially damage the corneal endothelium and/or rupture the naturallens capsule and associated zonules. Low glass transition temperatureacrylic materials are desirable because they typically have a highrefractive index and unfold more slowly and more controllably thansilicone materials when inserted into e.g., the lens capsule.Unfortunately, low glass transition temperature acrylic materials, whichcontain little or no water initially, may absorb pockets of water, invivo, causing light reflections or “glistenings”. Furthermore, it isdifficult to achieve ideal folding and unfolding characteristics due tothe temperature sensitivity of the acrylic polymers.

U.S. Pat. No. 5,480,950 issued Jan. 2, 1996 teaches of high refractiveindex hydrogel materials having a hydrated equilibrium water content ofat least 57% for use in the manufacture of IOLs. The high refractiveindex hydrogel materials are cross-linked polymers prepared frommixtures of N-vinylpyrrolidone, 4-vinylpyrimidine and a vinyl pyridinehaving equilibrium water contents up to 90% and refractive indexes of1.560 to 1.594 in the dry state. The IOLs as described are not implantedin a hydrated state. Rather, the IOLs are implanted in a dry, folded andelongated state and hydrated in situ. The refractive indexes in thehydrated state as used in the eye are not provided.

U.S. Patent Application Publication 2002/0049290 relates to highrefractive index (RI) ophthalmic hydrogel materials

U.S. Pat. No. 5,693,095 issued Dec. 2, 1997 teaches of high refractiveindex, low water content IOL materials. The materials taught in thisparticular patent are acrylic materials having an elongation of at least150%. IOLs manufactured from a material having such elongationcharacteristics will not crack, tear or split when folded. However, suchlow water content acrylic materials have been found to be lessbiocompatible than other materials when manufactured into and used asIOL devices.

In the past decade, hydrophobic polymers have been used in IOLmanufacturing with some success. The ophthalmic community has acceptedthis type of polymer as having good physical properties and acceptablebiocompatibility in ocular environments. However, current IOLs made fromconventional hydrophobic polymers sometimes suffer from poor opticalstability in ocular fluids (e.g. glistenings, optical artifacts) and lowrefractive indices. The formation of unwanted particles and deposits inthe bulk of hydrophobic polymers is attributed to uncontrolled watersorption and subsequent phase separation. Conventional homopolymerscurrently used to produce copolymers with high RIs (>1.51) absorbvarying amounts of water in a sporadic fashion, creating phaseseparation, haze, and glistenings.

Currently, there are no foldable, high RI IOL polymers that resist theformation of glistenings and deposits.

SUMMARY OF THE INVENTION

The present invention is a new family of high RI polymers particularlysuitable for, but not limited to, foldable IOL applications. Materialsof this invention are optically stable in ocular fluids and resist theformation of unwanted optical artifacts. The unusual properties of thecopolymers of this invention are achieved by creating nanoclusters of agenerally hydrophilic polymer within a very hydrophobic polymer matrix.Water sorption is minimized and limited to the nanoclusters. Inaddition, the limited amount of water that is absorbed is welldistributed and well dispersed within the matrix, preventing macrophaseseparation noted in prior art compositions. The approximate nanosizediameter of the clusters is in the range of 1.0 nm or less. Generallyspeaking the sizes of clusters operable in this invention will be of adiameter small enough so as to have little or interaction betweenvisible light and the polymer network. The result is an optically clearmaterial with stable optical properties.

This invention relates to novel copolymers for intraocular lenses(“IOL”), contact lens, and other ophthalmic and optical applications.IOLs made from the materials of this invention have a very highrefractive index, and may be machined at around room temperature. IOLsof this invention may be folded and used to replace a defective naturallens of the eye by insertion through a small incision without the needfor further processing or hydration. A particular advantage of thematerials of this invention is their unusual hybrid character thatprevents uncontrolled water sorption.

Foldable ophthalmic lens materials having controllable, uniform,relatively high water content and unexpectedly high refractive indicesparticularly suited for use as intraocular lenses (IOLs), or otherophthalmic devices such as but not limited to contact lenses,keratoprostheses and corneal rings or inlays, are the primary loci ofthe present invention.

This invention relates to copolymer compositions comprising limitedamounts of a monomer having, for example, a carbazole and/or naphthylmoiety, carbazole, naphthalene, or a naphthyl group and a hydrophobicmonomer. Carbazole and or naphthyl moiety monomers are added to thecomonomer to increase the refractive index of the comonomer and increasethe ability of the copolymer material to block blue light (wavelength upto 475 nm). A monomer having a surface tension generally in the range of50 dyn/cm or less is used to create a very hydrophobic matrix. Ahydrophilic polymer is added to create nanoclusters (in a processdescribed below) for controlled water sorption.

Accordingly, it is an object of the present invention to provide abiocompatible IOL material having a high refractive index.

Another object of the present invention is to provide an IOL materialhaving a high refractive index and controlled water sorption;

Still another object of the present invention is to provide an IOLmaterial that is relatively simple to manufacture.

These and other objectives and advantages of the present invention, someof which are specifically described and others that are not, will becomeapparent from the detailed description and claims that follow.

DETAILED DESCRIPTION OF THE INVENTION

Materials of the present invention with high refractive indexes aredesirable to allow manufacturers to manufacture thinner IOLs. A thin IOLor thin IOL optic is critical in enabling a surgeon to minimize incisionsize. Keeping the surgical incision size to a minimum reducesintraoperative trauma and postoperative complications. A thin IOL isalso critical for accommodating certain anatomical locations in the eyesuch as the anterior chamber and the ciliary sulcus. IOLs may be placedin the anterior chamber for increasing visual acuity in both aphakic andphakic eyes and placed in the ciliary sulcus for increasing visualacuity in phakic eyes.

The preferred materials of the present invention have the flexibilityrequired to allow the same to be folded or deformed so that IOLs madetherefrom may be introduced into an eye through the smallest possibleincision.

The novel materials of the present invention are copolymers, trimers,tetramers, etc., comprising three primary monomeric components: a highrefractive index (RI) monomer, a hydrophobic monomer, and a hydrophilicmonomer. A cross linker generally is included as is a UV absorber.

A high refractive index (RI) monomer of the present invention comprisesa fused ring aromatic moiety coupled to an ethylenically unsaturated orvinylically unsaturated moiety. By the term “high refractive indexmonomer” it is intended that a polymer of the high RI monomer (i.e., ahomopolymer of the monomer) has a refractive index of at least 1.50,preferably at least 1.53, and most preferably at least 1.56.

A vinylic or ethylene unsaturated moiety is, of course, well known tothe art generally to mean a structure of the sort,

wherein:

R₁-R₄ are separately and independently, H, C, X, or R_(c);

R_(c) is any hydrocarbon moiety; and

X is any heteratom, providing that at least one of R₁-R₄ must be a fusedring aromatic structure or moiety as is discussed below. The fused ringaromatic structure can be, and often is, R_(c).

“Fused ring aromatic” or polynuclear or polycyclic aromatic moietiesare, of course well known. These moieties are characterized by thepresence of at least two aromatic rings sharing a pair of carbon atoms.The best known examples of fused ring aromatic moieties are probablynaphthalene, carbazole, anthracene, and phenanthrene. Their moieties,i.e., naphthyl, anthracyl, carbazole, and phenanthryl, are examples ofpreferred moieties of the high RI monomer. Further examples of suchfused-ring aromatic molecules and hence their moieties include:

Fused Benzene Ring Compounds

The above list is, of course, non-limiting. Further, the unsaturationmoiety can be coupled to any one of the outer ring carbons of the abovestructures as would be readily apparent to one skilled in this art.

In a preferred practice, the high RI monomer comprises multimersincluding: a carbazole and or naphthyl moiety, the carbazole/naphthylmoiety monomer being present in the composition at a concentration of atleast 15% and preferably up to about 25-45%.

The composition further includes a second monomer with a hydrophobichomopolymer, the hydrophobicity being defined as the homopolymer havinga surface tension of about 50 dyn/cm or less, the second monomer beingpresent in the copolymer, in an amount of at least about 20 weightpercent, preferably about 50-60 weight percent.

The composition further includes at least about 10 weight percent of ahydrophilic monomer, preferably about 20-30 weight percent. Thecomposition then includes a crosslinking monomer, the crosslinkingmonomer being present at a concentration in the range up to 10 weightpercent, preferably of about 1 weight percent to about 8 weight percent.

Suitable hydrophilic monomers (i.e., monomers whose homopolymers arehydrophilic in accordance with this invention) include but are notlimited to 2-hydroxy-ethylacrylate, 2-hydroxyethylmethacrylate,acrylamide, N-ornithine acrylamide, N-(2-hydroxypropyl)acrylamide,polyethyleneglycol acrylates, polyethyleneglycol methacrylates, N-vinylpyrolidone, N-phenylacrylamide, dimethylaminopropyl methacrylamide,acrylic acid, benzylmethacrylamide, 4-hydroxybutylnethacrylate, glycerolmono methacrylate, glycerol mono acrylate, 2-sulfoethylmethacrylate,phenoxyethyl acrylate, phenoxy ethyl methacrylate,2-(2-ethoxyethoxy)ethyl acrylate, 2-(2-ethoxyethoxy)ethyl methacrylate,furfuryl acrylate, furfuryl methacrylate, and methylthioethylacrylamide.

Suitable hydrophobic monomers (i.e., monomers whose homopolymers arehydrophobic in accordance with this invention) include, but are notlimited to, Lauryl methacrylate, lauryl acrylate, 2-ethylhexyl acrylate,2-ethylhexyl methacrylate, n-decyl acrylate, n-decyl methacrylate, hexylacrylate, hexyl metcarylate, stearyl acrylate, stearyl methacrylate,isodecyl acrylate, isodecyl methacrylate, isobornyl acrylate, isobornylmethacrylate, vinyl laurate, vinyl stearate, 1-hexadecyl acrylate,1-hexadecyl methacrylate, n-myristyl acrylate, n-myristyl methacryalte,n-dodecyl methacrylamide, butyl acrylate, n-butyl methacrylate, isooctylacrylate, isotridecyl acrylate, isooctyl methacrylate, and isotridecylmethacrylate.

Suitable crosslinkers include, for example, but are not limited to,ethylene glycol dimethacrylate (EGDMDA), diethylene glycoldimethacrylate, and triethylene glycol dimethacrylate and poly (ethyleneglycol) dimethacrylate wherein ethylene glycol dimethacrylate ispreferred. Suitable initiators include, for example, but are not limitedto, azobis(isobutyronitrile), 2,2′-azobis(2,4-dimethylvaleronitdle),2,2′-azobis (methylbutyronitrile), 1,1′-azobis(cyanocyclohexane),di-t-butyl peroxide, dicumyl peroxide, t-butylcumyl peroxide,2,5-dimethyl-2,5-bis(2-ethylhexanoyl Peroxy)hexane, t-butylperoxyneodecanote, t-butyl peroxy 2-ethylhexanoate, di(4-t-butylcyclohexyl) peroxydicarbonate, t-butyl peroxypivalate, decanoylperoxide, lauroyl peroxide, benzoyl peroxide, 2,4-pentanedione peroxide,di(n-propyl) peroxydicarbonate, t-amyl peroxyneodecanoate and t-butylperoxyacetate wherein 2,2′-azobis(isobutyronitrile) is preferred.

Suitable ultraviolet light absorbers include for example but are notlimited to beta-(4-benzotriazoyl-3-hydroxyphenoxy)ethyl acrylate,4-(2-acryloxyethoxy)-2-hydroxybenzophenone,4-methacryloxy-2-hydroxybenzo-phenone,2-(2′-methacryloxy-5′-methylphenyl)benzotriazole,2-(2′-hydroxy-5′-methacryoxyethylphenyl)-2H-benzo-triazole,2-[3′-tert-Butyl-2′-hydroxy-5′-(3″-methacryloyloxypropyl)phenyl]-5-chloro-benzotriazole,2-(3′-tert-Butyl-5′[3″-dimethylvinyisilylpropoxy)-2′-hydro-xyphenyl]-5-methoxybenzotriazole,2-(3′-Allyl-2′-hydroxy-5′-methylphenyl)benzo-triazole,2-[3′-tert-Butyl-2′-hydroxy-5′-(3″methacryloyloxypropoxy)phenyl]-5-methoxybenzotriazole,and2-[3′-tert-Butyl-2′-hydroxy-5′-(3″-methacryloyloxypropoxy)phenyl]-5-chlorobenzo-triazolewherein beta-(4-benzotriazoyl-3-hydroxyphen-oxy)ethyl acrylate is thepreferred ultraviolet light absorber.

A UV absorber optionally may be added to the copolymer compositions. Anovel, preferred, UV/blue light absorber, i.e., vinyl anthracene, may beadded to the copolymer compositions. Conventional U.V. absorbers such asa vinyl benzophenone or a vinyl benzotriazole also may be used.

A monomeric dye capable of copolymerizing with the hydrophobic and thehydrophilic monomers optionally may be added to the copolymer toattenuate specific wavelengths of light. Such dyes include but are notlimited to those containing vinyl groups and are capable of absorbingviolet, blue, red, and green light in the range of 400-700 nm.

Examples of such monomeric dyes include but are not limited to:

Disperse Red 13 acrylate,Disperse Orange 3 acrylamideDisperse Orange 3 methacrylamideDisperse Red 1 methacrylateDisperse Red 1 acrylateDisperse Red 13 methacrylateDisperse yellow 7 acrylateDisperse yellow 7 methacrylateEthyl trans-α-cyano-3-indoleacrylate[(S)-(−)-1-(4-Nitrophenyl)-2-pyrrolidinemethyl]acrylate

General Preparation Steps for Polymers of Examples 1-15

The comonomers listed below were mixed in a glass flask using a magneticstir bar for at least 30 minutes, at room temperature followed bysonication for the times indicated, and then stirring again for another30 minutes. The combination of sonication and hydrophilic/hydrophobicrepulsion forces allows the formation of nanoclusters. The size of thenanoclusters is theoretically controlled by the amount of energyprovided during these steps. It was found that sonicating for about 30minutes at a power setting of 100% on a Branson 5510 sonicator providesoptically clear materials with adequate optical and physical properties.Sonicating time may vary between 1 minutes to 60 minutes depending onthe formulation used. It has also been found that an optional secondsonication step of at least about 10 minutes is sometimes needed toproduce materials of the desired optical characteristics.

The resulting copolymers are rigid enough to be machined at around roomtemperature. A unique and surprising aspect of the above materials isthat the refractive index of the copolymers is so high that ophthalmiclenses can be made thin enough to be folded without further processingor hydration.

Examples 1-15

Processing Monomer Cocentration RI % EWC conditions Ex. 1 VC 30 1.56901.5 20 minutes LM 37 sonication twice HEMA 30 EGDM 3 Ex. 2 VC 30 1.56871.7 25 minutes LM 37 sonication twice HEA 30 EGDM 3 Ex. 3 VC 30 1.56341.8 15 minutes EHA 37 sonication HEMA 30 EGDM 3 Ex. 4 VC 30 1.5623 1.715 minutes EHA 37 sonication HEA 30 EGDM 3 Ex. 5 VN 30 1.5541 1.7 10minutes EHA 37 sonication HEMA 30 EGDM 3 Ex. 6 VC 30 1.5512 1.6 10minutes EHA 37 sonication HEA 30 EGDM 3 Ex. 7 VC 25 1.5476 1.4 15minutes EHA 52 sonication HEMA 20 EGDM 3 Ex. 8 VC 25 1.5442 1.7 15minutes EHA 52 sonication HEA 20 EGDM 3 Ex. 9 VC 35 1.5623 1.7 10minutes EHA 47 sonication HEMA 15 EGDM 3 Ex. 10 VC 35 1.5601 1.1 15minutes EHA 47 sonication twice HEMA 10 EGDM 3 Preferred FormulationsEx. 11 VC 30 1.5590 1.2 30 minutes EHA 42 sonication HEMA 25 EGDM 3 Ex.12 VC 27.5 1.5510 1.0 30 minutes LM 44.0 sonication twice HEA 25.5 EGDM3 Ex. 13 VC 27.0 1.5500 1.0 30 minutes LM 42.0 sonication twice HEA 24.0EGDM 0.25 VA 0.45 Ex. 14 VC 27.0 1.5511 1.0 30 minutes LM 44.5sonication twice HEA 25.0 EGDM 2.5 DR1 0.02 Ex. 15 VC 27.0 1.5505 1.0 30minutes LM 44.5 sonication twice HEA 25.0 EGDM 2.5 DR1 0.01 2.5% byweight of VA and 0.3% by weight of MEB was used in all copolymercompositions. VC: vinyl carbazole VN: 2-vinyl naphthalene EHA:2-ethylhexylacrylate LM: Lauryl methacrylate HEMA;Hyroxyethylmethacrylate HEA: Hydroxyethylacrylate EGDM: ethylene glycoldimethacrylate VA: vinyl anthracene MEB:2-(2′-Methacryloxy-5′methylphenyl)benzotriazole DR 1: Disperse Red 1Methacrylate

1. A composition comprising: a high refractive index monomer comprisinga carbazole or naphthyl moiety, carbazole, naphthalene or a naphthylgroup; a hydrophobic monomer, a hydrophilic monomer, and a crosslinker.2. The composition of claim 1, wherein said composition includes anultraviolet light absorbing material.
 3. The composition of claim 1,wherein said composition includes an ultraviolet light absorbingmaterial selected from the group consisting ofbeta-(4-benzotriazoyl-3-hydroxyphenoxy)ethyl acrylate,4-(2-acryloxyethoxy)-2-hydroxybenzophenone,4-methacryloxy-2-hydroxybenzo-phenone,2-(2′-methacryloxy-5′-methylphenyl)benzo-triazole,2-(2′-hydroxy-5′-methacryoxy-ethylphenyl)-2H-benzotriazole,2-[3′-tert-Butyl-T-hydroxy-5′-(3″-methacyloyloxypropyl)phenyl]-5-chlorobenzotriazole,2-(3′-tert-Butyl-5′-(3-dimethylvinylsilylp-ropoxy)-2′-hydroxyphenyl]-5-methoxybenzo-triazole,2-(3′-Allyl-2′-hydroxy-5-′-methylphenyl)benzotriazole,2-[3′-tert-Butyl-2′-hydroxy-5′-[3″-methacryloyl-oxypropoxy)phenyl]-5-methoxybenwtriazoleand2-[3′-tert-Butyl-2′-hydro-oxy-5′-(3″-methacryloyloxypropoxy)phenyl]-5-chloro-benzotriazole.4. A composition of claim 1, wherein the ultralight absorbing materialis vinyl anthracene or derivatives there.
 5. The composition of claim 1,wherein said composition includes a monomeric dye.
 6. A composition ofclaim 1, wherein the monomeric dye absorbs light in the 400-700 nmregion.
 7. A composition of claim 1, wherein the monomeric dye isdisperse red 1 methacrylate.
 8. A composition of claim 1, wherein themonomeric dye is disperse red 13 methacrylate.
 9. A composition of claim1, wherein the monomeric dye is disperse red 1 acrylate.
 10. Acomposition of claim 1, wherein the monomeric dye is disperse red 13acrylate.
 11. A composition of claim 1, wherein the hydrophilicmonomer(s) is selected from the group consisting of2-hydroxy-ethylacrylate, 2-hydroxyethylmethacrylate, acrylamide,N-ornithine acrylamide, N-(2-hydroxypropyl)acrylamide,polyethyleneglycol acrylates, polyethyleneglycol methacrylates, N-vinylpyrolidone, N-phenylacrylamide, dimethylaminopropyl methacrylamide,acrylic acid, benzylmeth-acrylamide, 4-hydroxybutylmethacrylate,glycerol mono methacrylate, glycerol mono acrylate,2-sulfoethylmethacrylate, phenoxyethyl acrylate, phenoxy ethylmethacrylate, 2-(2-ethoxyethoxy)ethyl acrylate, 2-(2-ethoxyethoxy)ethylmethacrylate, furfuryl acrylate, furfuryl methacrylate, andmethylthioethylacrylamide.
 12. A composition of claim 1, wherein thehydrophobic monomer(s) is selected from the group consisting of Laurylmethacrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-ethylhexylmethacrylate, n-decyl acrylate, n-decyl methacrylate, hexyl acrylate,hexyl metcarylate, stearyl acrylate, stearyl methacrylate, isodecylacrylate, isodecyl methacrylate, isobornyl acrylate, isobornylmethacrylate, vinyl laurate, vinyl stearate, 1-hexadecyl acrylate,1-hexadecyl methacrylate, n-myristyl acrylate, n-myristyl methacryalte,n-dodecyl methacrylamide, butyl acrylate, n-butyl methacrylate, isooctylacrylate, isotridecyl acrylate, isooctyl methacrylate, and isotridecylmethacrylate.
 13. A copolymer comprising: a) a high refractive indexmonomer comprising a fused ring aromatic moiety coupled to a vinylicallyunsaturated moiety; b) a hydrophobic monomer; and c) a hydrophilicmonomer.
 14. A copolymer of claim 13 wherein the high refractive indexmonomer comprises:

wherein: R₁-R₄ are separately and independently, H, C, X, or R_(c);R_(c) is any hydrocarbon moiety; and X is any heteratom, providing thatat least one of R₁—R₄ must be a fused ring aromatic structure.
 15. Acopolymer of claim 13 wherein the high refractive index monomercomprises an ethylenically unsaturated moiety and a fused ring aromaticmoiety.
 16. A copolymer of claim 15 wherein the ethylenically saturatedmoiety comprises:

wherein: R₁, R₃ and R₄ are separately and independently, H, C, X, orR_(c); R_(c) is any hydrocarbon moiety; and X is any heteratom.
 17. Acopolymer in accordance with claim 13, wherein the high refractive indexmonomer is selected from the group consisting of vinyl carbazole, vinylnaphthalene, and vinyl anthracene.
 18. A copolymer according to claim 13which comprises: a) at least about 15% by weight high refractive indexmonomer; b) at least about 20 weight percent hydrophobic monomer; c) atleast about 10 weight percent hydrophilic monomer.
 19. A copolymeraccording to claim 18 wherein the high refractive index monomer isselected from the group consisting of vinyl naphthalene, vinylcarbazole, and vinyl anthracene.
 20. A method of making a highrefractive index copolymer comprising the steps of a) providing amixture of monomers specified in claim 1; b) mixing the monomer for atime period of at least 20 minutes at about room temperature; c)sonicating the mixture of monomers for a time period of at least 10minutes at about room temperature to produce copolymer nanoclusters insubstantially hydrophobic matrix.
 21. A method according to claim 20which includes a further step of mixing the sonicated mixture for a timeperiod of at least about 15 minutes.